'01 Cavalier showing "not ready" for emissions test

[Highmarker]

This is a brain racker for me. Here we go:

I have a 2001 Cavalier that was up for emissions test in June in Weber County in Utah. For those of you not in Utah, the rule is if the vehicle has OBDII system, then the system has to be operating correctly. They do not check what is coming out of the tailpipe. I went to have my emission test done, and it came up saying "not ready". I had two sensors say "not ready" (the CATALYST and the EVAP SYSTEM). I was told to drive it around (drive cycle) to try and get the computer to "reset" the sensors.

After 400 miles driving around and stopping and starting countless times, still no reset of the sensors. I called Young Chevrolet, and they told to drive around some more. I called Jerry Seiner Chevrolet and they said the same thing. It seems that everybody has their own version of a "drive cycle". I talked to a gentleman at the Salt Lake County Emissions and he said that this is not uncommon for these bi-fuel Cavaliers to not reset the sensors. In fact in Salt Lake County, they will allow the tailpipe test for natural gas vehicles if the sensors are not able to be reset. However, I live in Weber County, and they will not allow the tailpipe test to be used if the vehicle has the OBDII system.

So here I am still driving my Cavalier around trying to get the computer to reset the sensors.

Any ideas?

[CNGfamily]

Re: '01 Cavalier showing "not ready" for emissions test

This is a brain racker for me. Here we go:

I have a 2001 Cavalier that was up for emissions test in June in Weber County in Utah. For those of you not in Utah, the rule is if the vehicle has OBDII system, then the system has to be operating correctly. They do not check what is coming out of the tailpipe. I went to have my emission test done, and it came up saying "not ready". I had two sensors say "not ready" (the CATALYST and the EVAP SYSTEM). I was told to drive it around (drive cycle) to try and get the computer to "reset" the sensors.

After 400 miles driving around and stopping and starting countless times, still no reset of the sensors. ...

Any ideas?

If this vehicle OBD II is similar to the Civic GX, you will get this error with a blown fuse in one of the circuits supplying power to the computer... I don't recall which one, but I believe it may be the power feed that also supplies 12V all the time to keep radio memory settings, etc.
In our case, it took a couple extra tries at the SMOG station, then a couple visits to the dealer to get them to check for the blown fuse... you'd get the same error if you disconnected the battery and went to emissions right away. Anyway, EVERYONE says "drive it around for a while and it will clear..." that's true only if you have not started, driven around a couple miles and stopped the engine a very few times.

Good luck

[krnorth]

Re: '01 Cavalier showing "not ready" for emissions test

This is more than likely NOT a blown fuse. It is possible if your check engine lite is on all the time.

However, I have a 2000 cavalier and had the same problem. In order for the car to pass the test you must have a readiness of 6 out of 7.

I drove the car around a billion miles it seemed and I "NEVER" got the readiness up where it needed to be. After rebuilding my low pressure regulator I was able to place a "monitor" on the computer plug which beeps at you when the readiness is passable.

What did rebuilding the LRP have to do with it? well the fact that I had a check engine light, it was due to the fact that the mass gas sensor was tripping my check engine light because the flow of gas was improper. Once it was rebuilt my sensor was happy again and cleared my light.

However, even AFTER rebuilding that I found (with the help of the computer monitor) that if I turned the key off my readiness would drop back down to 3 out of 7 (OBDII NOT READY).

I drove it around for about 45 miles and ran it back to the shop and my readiness was 6 out of 7. Good enough for a pass. However, I explicity instructed them to NOT turn my car off otherwise it would reset the computer readiness check. So basically I drove it around about 20-30 miles and drove it into the shop and said...DO NOT TURN MY CAR OFF!!! I explained why.

My car passed with 6 out of 7 (as would yours). Also, my EVAP system was the only one that did not clear. It's hard to say exactly what your problem is, I just know that within 15-20 miles my readiness would get 6 out of 7.

Also, my mechanic said your gas gages should be between 3/8 and 3/4 (no more and no less)...this is when the computer peforms readiness checks. This applies to BOTH tanks (CNG AND GAS)...so make sure they are both within that range, then drive it around and you should get it to 6 out of 7 at least.


I hope this helps, let me know how it goes, I know I was frustrated when trying to pass my emissions with it!!

[Highmarker]

Re: '01 Cavalier showing "not ready" for emissions test

My "check engine" light is NOT on. I know that the EVAP sensor is for the gasoline only. I am going to run to Checker Auto Parts tonight and use their I/M Monitor Status and see if they are "ready".

krnorth, tell me more about this "monitor" that you built and hooked to your computer.

[Larryect]

Re: '01 Cavalier showing "not ready" for emissions test

The ScanGuage product will tell you if the OBD system is Ready.

http://www.scangauge.com/products/

No afilliation. Nice tool for MPG as well.

[krnorth]

Re: '01 Cavalier showing "not ready" for emissions test

Checker & Auto Zone do not have scanners that will tell you the "readiness", I tried that previously.

I did not build anything for the car, it's a readiness monitor for the computer that you plug into the port below your steering column. You can purchase them from a dealer (they are a bit pricy). My mechanic friend has one and he lent me his. I would recommend the driving around and getting your mechanic to scan it to check it but do NOT turn the car off. Drive it around 30 miles and then have them scan it without turning the key or engine off.

[freedml]

Re: '01 Cavalier showing "not ready" for emissions test

One thought. What if you drive it around ON GASOLINE for a while? Leave the CNG computer off and let the gasoline computer show 'ready.'

I use an AutoTap interface to my laptop to read error codes, engine parameters and 'readiness.'

[Highmarker]

Re: '01 Cavalier showing "not ready" for emissions test

That is a big question for me too. I have ran both CNG and gasoline - No luck yet. Right now I have "locked out" my CNG tank and I am running on gasoline. This is not a problem for the '03 and '04 models - they don't have a CAT nor an EVAP sensor.

I am going to try and run the emission test without shutting the car off. I'm keeping my fingers crossed.

[krnorth]

Re: '01 Cavalier showing "not ready" for emissions test

I tried the "running" around on gas thing as well, this did not work. Once I fixed my LPR everything cleared up for me and my car cleared right up.

If you have any further questions let me know. Keep us posted.

[Highmarker]

Re: '01 Cavalier showing "not ready" for emissions test

I got it to pass. Thanks to krnoth and everybody else. Here's what I did:

1. I locked out my CNG tank (tightening the allen wrench on the solenoid valve) and ran my car until it switched over to gasoline.
2. I shut my car off and started it up on gasoline. I then shut my car off.
3. I removed the battery cables and touched the negative cable and the positive cable together for about 10 seconds. This drained the energy out of everything. I then reconnected the battery cables to the battery.
4. I then drove around for about 20-30 miles on gasoline. Most of this consisted of cruising at 55 mph.
5. I then went to the emission testing shop and told them to NOT turn the car off.
6. They ran the emissions test while the car was running the whole time.
7. It passed.
8. I then turned the car off and unlocked my CNG tank and it started on CNG.

As a side note. All my sensors were ready even the EVAP SYS sensor.

[krnorth]

Re: '01 Cavalier showing "not ready" for emissions test

That's good to hear! Problems can be frustrating, glad you got it worked out.